adding the melpa package repository

This change was suggested by ViktorHaag on github.
perhaps this does it?
corrected yasnippet startup
Finish feature-replace-yasnippet-bundle
replaced yasnippet-bundle with yasnippet
fix bug installing yasnippet over yasnippet-bundle

  Without this check the new yasnippet install throws errors if the old
  yasnippet-bundle has not been deleted.  Better to add two lines to
  starter-kit.org than have every user run into this problem on their
  next update.
Upstream update merged